This invention relates to a plug assembly for installation in liquid waste disposal units such as domestic wash basins, bath tubs and the like. In the past, drain closures for such units generally consisted of a socket portion and a plug which was designed with a tapered wall to permit its forced insertion into the socket where it remained secured in a friction bond with the walls of the socket until it was manually removed. Since the plug and the socket were separate elements, various means were provided for anchoring the plug, such as chains or other forms of fastening devices. In recent years the configuration of such plugs have changed in some instances to a dome type structure, but in all cases these structures are separate from a socket portion, maintain their original configuration, and require separate fastening devices to secure them within the socket to prevent drainage. U.S. Pat. No. 3,366,980 to Petursson represents a departure from the conventional type drain plug in that the plug and the socket are fastened together, the plug being provided with a pop-up feature which permits movement of the plug from a fully-opened position to a fully-closed position within the drain socket. Nevertheless, in order to maintain the plug or stopper in its closed position the patent requires a catch member. In addition the patent retains the concept of maintaining the plug in a single configuration; the plug simply being moved up and down between an open and closed position.